I have a Averatec laptop that I dual boot. I get better power management under Ubuntu Linux than I do under Windows XP - with similar 'power saving' settings. I am almost sure that this is because there are fewer memory and CPU hungry processes running under Linux. So, when I am reading online, under Linux it is easier to shut down the disk and fan because everything runs in memory and the CPU is largely idle.
Speaking of Windows XP, although in some instances it is a good OS for coding, it always makes me a little uncomfortable having so much stuff installed by default. Although I wrote a commercial Windows product (SAIC ANSim) using Windows 1.0 beta and delivered on Windows 1.0 and 1.03, Windows NT was the first version of Windows that I liked. I had a "secret" for using Windows NT effectively: I had one boot partition that was totally stripped of everything but my software development tools and another that I would load a bunch of junk on - the trimmed down version with no spurious applications installed was incredibly stable. I have thought of doing the same thing for Windows XP but I don't think that XP's copy protection would let me do this.
I used to use a shared FAT32 partition to share design artifacts and source code between dual booted operating systems, but now it is just so much easier to keep everything in a CVS repository on a server. As I mentioned the other day, this makes it easy to use Windows Linux, or OS X for a task, picking the best platform per job.